If anyone can help it would be much appreciated. Complete newbie to the codec world. I have a dvr that encodes everything in mpeg4-h264. However, when any files are transferred to my pc they do not play back. They are mp4 files. I have a PC ( not mac) and I've tried opening the files in Quicktime, Real Player, and Windows Media Player. I have the most recent updates for each. Can anyone help me? I have a utility that came with the DVR to convert the mp4 to avi files but it seems to convert at a smaller resolution.

Any help would be appreciated. If this is a simple answer I apologize in advance if my novicity is bordering on stupidity. Thanks.

Try FFDShow, set it to decode h.264. If don't know how, see this topic.

I downloaded FFDShow and clicked on decode h.264 and then said 'apply'. When I tried to open one of these mp4 files I still got the message "Error-2048: the file is not a movie file" Still can't play.

MediaCoder is an excellent transcoder/recoder with support for H.264 encoded files. It will take you only a couple of minutes to recode the file; you can choose MPEG-4 (DivX 4-5).

If you still have problems playing the files, try to change their fourcc code with AVI FourCC Changer. Sometimes you don't even need to to transcode or recode the files

Thanks, I've tried botht the MediaCoder and the AVIFourCC changer and neither worked. The MediaCoder at first transcribed a file but the new file had 0KB. After that first attempt all other attempts resulted in the error message:
Nothing is transcoded, please check the log....

The FourCC Changer, I changed the setting, it said they were changed, but I still couldn't open the file. I'm attaching a 5 second file. Can you see if you can open it? And, if so, could you tell me how you accomplished it? Thanks.